Background: Despite the recent advances in this area, colic remains a major cause of morbidity and death in horses. Neutrophilic activation and degranulation may play a key role in the postoperative ... [more ▼]

Background: Despite the recent advances in this area, colic remains a major cause of morbidity and death in horses. Neutrophilic activation and degranulation may play a key role in the postoperative complications. Activated neutrophils release enzymes like proteases and myeloperoxidase (MPO). MPO concentrations in plasma and tissue are considered as a marker of neutrophil activation. (McConnico et al. 1999; Hoy et al. 2002). When freed in the tissue, active MPO is able to oxidize, nitrate and chlorate most organic molecules (Klebanoff 2005). Objectives: The aim of this study was 1) to determine the time trends of blood leukocyte and neutrophil counts as well as of plasmatic MPO concentrations in the perioperative period of horses undergoing colic surgery and 2) to relate these time trends to the location of the pathology, the severity of postoperative complications and to the outcome of the patients. Methods: Fifty two horses undergoing colic surgery at the Equine Teaching Hospital of the University of Liege were included in this study. The location of the predominant lesion of the intestine, the severity of the postoperative complications and the outcome were recorded for each horse. Total leukocyte and neutrophil counts were performed in all of the horses while plasmatic myeloperoxidase levels were determined in 16 of them. The blood samplings were realized before and during the surgery (after correction of the intestinal lesion), during the recovery and every 4 hours during the first 4 days (from day 0 until day 4) and then every 12 hours until day 6 (150th hour after the first blood sampling) or until euthanasia. Hematologic analyses were performed at the time of sampling by use of the Medonic CA 530 (Menarini, Zaventem, Belgium). The blood was then centrifuged and the plasma was aliquoted and frozen at -20° C until assayed. MPO was assayed with a specific enzyme-linked immunosorbent assay (Equine MPO-ELISA kit, BiopTis, Liège, Belgium). A mixed model was used to analyze the time trends of leukocytes, neutrophils and MPO. All computations were done with the SAS (Statistical Analysis System) procedure Proc Mixed, with Satterthwaite degrees of freedom. The significance level was set at p=0.05. Results: The main pathology was found in the large intestine in 30 horses (58%) and the small intestine in 22 horses (42%). Forty horses (77%) survived to discharge from the clinic. Twelve horses were euthanized during the postoperative period. Their survival time varied from 0.5 day to 20 days with a mean of 7.8 days. Twenty-two horses (42%) showed none or mild complications, 12 horses (23%) showed moderate complications and 18 horses (35%) suffered from severe complications. Time trends for leukocytes and neutrophils were similar to each other (p= 0.7205) and significantly different (p< 0.0001) from the MPO time trend, which increased during the first hours, while the neutrophil time trend decreased immediately after the admission. The time trend of neutrophils was higher in large intestinal than in small intestinal pathologies and the time trend of MPO was lower in large intestinal than in small intestinal pathologies. The time trends of neutrophils were significantly different between the degrees of complications (no/mild vs moderate vs severe). For the first part of the curve, the more severe the complication, the lower is the time trend. The time trend of MPO was lower in survivors. The time trend of neutrophils in survivors was higher during the first 4 days thereafter it becomes lower than in non survivors. Conclusions: These results confirm that neutrophil counts and MPO levels undergo timely changes and that they are related to the severity of the inflammatory reaction in surgical colic cases. Knowing the kinetics of these parameters is an essential step to further determine cut-off values (with a larger group of horses) for the prognosis of horses after colic surgery. References Hoy, A., Leininger-Muller, B., Kutter, D., Siest, G. and Visvikis, S. (2002) Growing significance of myeloperoxidase in non-infectious diseases. Clin. Chem. Lab. Med. 40, 2-8. Klebanoff, S.J. (2005) Myeloperoxidase: friend and foe. J. Leukoc. Biol. 77, 598-625. McConnico, R.S., Weinstock, D., Poston, M.E. and Roberts, M.C. (1999) Myeloperoxidase activity of the large intestine in an equine model of acute colitis. Am. J. Vet. Res. 60, 807-813. [less ▲]

Echocardiography has become a routine non invasive cardiac diagnostic tool in most species. Accurate measurement of cardiac dimensions requires reference values, which are poorly documented in goats ... [more ▼]

Echocardiography has become a routine non invasive cardiac diagnostic tool in most species. Accurate measurement of cardiac dimensions requires reference values, which are poorly documented in goats. Goats are animals easy to handle with a body and heart size comparable to humans’. This makes goats an attractive candidate for the development of animal models for human cardiology research. The aim of this study was to test the repeatability and to establish the reference values of bi-dimensional (2D-), time-motion (M-) mode and pulsed wave (PW) Doppler echocardiographic variables in adult goats. Six healthy female adult Saanen goats were investigated three times by the same observer at one day interval using a standardized 2D-, M-mode and PW Doppler echocardiographic protocol. Calculation of the coefficient of variation for each variable measured within day and depending on the day allowed to evaluate their degree of variability. A single echocardiographic examination was performed in 6 other goats by the same observer, and the obtained values were added to these obtained on the third day of the 6 first goats. Then the observed mean, the standard deviation and the range of these measurements were calculated to establish the reference values of echocardiographic parameters in unsedated adult healthy female Saanen goats. Statistical analysis revealed a good inter-day repeatability of the 2D- and M-mode echocardiographic cardiac measurements, but PW Doppler parameters presented moderate to high variability, as documented in other species. Echocardiographic reference values obtained in healthy adult Saanen goats were similar to those reported in healthy adult sheep and in healthy adult humans. [less ▲]

Acepromazine (ACP) is a phenothiazine commonly used to sedate horses. Additionally, ACP exerts strong anti-inflammatory effects, which might have a therapeutic potential in horses suffering from systemic ... [more ▼]

Acepromazine (ACP) is a phenothiazine commonly used to sedate horses. Additionally, ACP exerts strong anti-inflammatory effects, which might have a therapeutic potential in horses suffering from systemic inflammatory response syndrome (SIRS). However, the ACP-induced vasodilation precludes its use in horses with SIRS-related cardiovascular compromise. The objective of this study was to test if the hemodynamic effects of the administration of 0,1 mg/kg of ACP could be counteracted by an intravenous infusion of norepinephrine (NOR) at 1ug/kg/min in healthy horses. In 5 healthy adult horses, a 15 minutes NOR IV infusion was administered 45 minutes after an injection of 0,1 mg/kg of ACP IV. The systolic arterial blood pressure (SAP) was non-invasively measured by Doppler sphingometry at the tail. Hemodynamics of the median artery of the left forelimb were studied using Doppler ultrasonography, through calculation of the vessel’s surface (SURF), diameter (DIAM), circumference (CIRC), and peak systolic velocity (PSV), end diastolic velocity (EDV), mean velocity (MV), volumetric flow (VF) and resistivity index (RI) of the flow. Both SAP and Doppler parameters were determined at regular intervals during the entire study. ACP induced a hypotension and a vasodilatation, that were evidenced by a significant rise of the SURF, DIAM, CIRC, PSV, EDV, MV and VF and reduction of the SAP and RI. During NOR infusion, all these ACP-induced hemodynamic changes were reversed. These findings suggest that a continuous IV NOR infusion at 1ug/kg/min is able to revert ACP-induced hypotension and vasodilation in healthy adult horses. [less ▲]

After ingestion of moulded beet pulp silage, cases of cerebro-cortical necrosis (CCN) and mortalities were observed in a dual purpose Belgian Blue (BB) herd. Contamination with Paecilomyces spp., a mould that produces byssochlamic acid, malformins and patulin, was proven. Twenty-five days after progressive introduction of beet pulp silage into the ration, most of the animals showed diminished appetite, excessive salivation and decreased milk production. Some of them showed anorexia, head pressing and blindness while 4 animals died within 1 week after onset of neurological symptoms. The survivors had been treated successfully with thiamine and recovered completely within five days. Once the beet pulp silage had been identified as causative agent, it was removed from the animals’ ration and no more clinical cases were observed. Silage was obviously moulded and analysis revealed the presence of 1.6 million CFU Paecilomyces spp./g of silage. Although no further investigation was undertaken to identify the mycotoxins, intoxication with patulin was suspected, since other mycotoxins produced by these species are less toxic. Although it has not been described that CCN can be induced by ingestion of Paecilomyces spp., it seems that there is a close relation between ingestion of Paecilomyces-contaminated silage and clinical signs observed in this herd. [less ▲]

Endotoxemia is the first mortality cause in equine intensive care. In humans with septic shock, some echocardiographic indicators are used to predict the efficiency of fluid resuscitation and outcome ... [more ▼]

Endotoxemia is the first mortality cause in equine intensive care. In humans with septic shock, some echocardiographic indicators are used to predict the efficiency of fluid resuscitation and outcome, allowing an early-goal-directed therapy. Echocardiography has never been investigated for this indication in horses. The aim of this study was to assess the prognosis value of echocardiographic and Doppler parameters of left ventricular (LV) function in horses with severe endotoxic shock. Twenty-one horses admitted to the clinic for colic with clinical signs of severe endotoxic shock underwent Doppler echocardiographic examination. LV echocardiographic and Doppler parameters were compared between the survivors (n=6) and the non-survivors (n=15) horses using a multivariable ANOVA analysis. The pre-ejection period to ejection time ratio (PEP/ET) of the Doppler aortic flow was significantly higher in the non-survivors than in the survivors group. All other measured parameters (including heart rate and end-diastolic-volume) were not significantly different between the groups. Doppler parameters of left ventricular function are subject to high variability and low repeatability in horses. This might explain that most variables were not significantly different between the two groups. Moreover, the number of investigated horses was limited, especially in the survivors group. However, with comparable HR and LV preload, a higher PEP/ET suggested a more compromised systolic dysfunction in the non-survivors. PEP/ET is often considered to be one of the best indicators of systolic function in horses and its measurement might therefore be useful in indicating the need for inotropic support in the management of horses with endotoxic shock. [less ▲]

Angiotensin converting enzyme inhibitors are recommended therapy in human and canine patients with congestive heart failure (CHF), but little is known concerning their efficiency to treat horses with CHF ... [more ▼]

Angiotensin converting enzyme inhibitors are recommended therapy in human and canine patients with congestive heart failure (CHF), but little is known concerning their efficiency to treat horses with CHF. Enalapril has been shown to be poorly absorbed in horses and quinapril has been shown to decrease the severity of the insufficiency and to increase the stroke volume (SV) and the cardiac output (CO) in horses with mitral regurgitation (MR) without signs of CHF. The objective of this cases report was to evaluate the effect of quinapril associated with routine treatment in horses with CHF. Three horses with clinical, echocardiographic and electrocardiographic signs of severe MR, CHF and secondary atrial fibrillation were studied (Fig 1 to 3). None of them had been previously treated for those problems. According to the ACVIM classification system for management of canine CHF, they were therefore classified in class C. They were treated with quinapril 0.2mg/kg SID PO, digoxin 0.011mg/kg BID PO, and furosemide 1mg/kg BID IM. Standard echocardiographic and Doppler measurements were performed before treatment (T0), and 1 and 4 weeks after starting treatment (W1 and W4, respectively). All horses showed a transient clinical improvement (decrease of edemas and disappearance of the dyspnea) after 1 week of treatment, but clinical signs deteriorated within the following weeks in 2 horses that were euthanized for ethical reasons. The third horse kept a steady clinical status and was discharged with the treatment pursued at home. Evolution (in %) of main echocardiographic parameters at W1 and W4 compared to T0 values are showed in Table1. Large individual variations in response to the treatment were seen. Nevertheless, in all horses, a decrease of the Heart Rate (HR) was observed after 1 week of treatment, but the HR increased again after 1 month of treatment (Fig 4). On the contrary, no increase in SV or CO, and no decrease in LVIDd were seen in response to treatment (Fig 5). In the 2 horses that were euthanized, the fractional shortening (FS) and the pre-ejection to ejection time ratio (PEP/ET) decreased and the mitral E peak velocity increased with treatment, whereas they followed the opposite evolution in the surviving horse. No conclusion can be drawn from this study because of the limited number of studied cases. However, it would be interesting to extend it to additional cases and to less severely affected cases (i.e. horses classified in class C after initial treatment or class B horses). Negative chronotropic effect of digoxin was suggested after 1 week of treatment since a decrease of the HR was observed in all horses. However, this effect seemed to decrease after 1 month of treatment. Those preliminary results of echocardiography suggest that quinapril in association with digoxin and furosemide at the used dosage could be inefficient to reduce the left ventricular filling pressure and to improve the myocardial contractility in horses with severe CHF. This could however be due to the fact that the 3 studied horses were cases refractory to classic treatment (thus to be classified in class D). [less ▲]

Background: Echocardiography has not been reported to study hemodynamic disturbances in colic horses. Objectives: To non invasively assess the impact of colic-related endotoxin shock on equine cardiac ... [more ▼]

Background: Echocardiography has not been reported to study hemodynamic disturbances in colic horses. Objectives: To non invasively assess the impact of colic-related endotoxin shock on equine cardiac function. Animals: Fifty horses admitted in clinic on emergency for colic. Methods: A shock score from 1 to 4 was established for each horse based on clinical evaluation, non invasive systolic blood pressure and blood tests measurements. Left ventricular echocardiographic and Doppler parameters were compared between the 4 groups according to the shock score (1 = no or discrete signs of shock, n=11; 2 = mild shock, n=17; 3 = moderate shock, n=12; 4 = severe shock, n=10) using a multivariable analysis. Horses with a score shock of 1 were considered as control. Significance was set at P < 0.05. Results: The stroke volume, stroke index, ejection time, ejection time index corrected for heart rate, aortic velocity time integral, aortic flow acceleration time and aortic flow deceleration time were significantly lower whereas acceleration rate of aortic flow ejection and heart rate were significantly higher in shocked horses than in controls. Cardiac output was not significantly different between groups. Conclusions and Clinical importance: Even if those results are difficult to interpret because of the shock-induced changes in loading conditions of the heart, they suggest that alterations in some indicators of systolic function can be quantified by Doppler echocardiography in horses with colic-induced endotoxemic shock. Ultrasonographic monitoring of cardiovascular function could thus be of interest in equine intensive care. [less ▲]

Bovine ehrlichiosis is a tick-borne rickettsial disease caused by Anaplasma phagocytophilum. The disease can also be transmitted to humans. Outbreaks in cattle have been described in many European ... [more ▼]

Bovine ehrlichiosis is a tick-borne rickettsial disease caused by Anaplasma phagocytophilum. The disease can also be transmitted to humans. Outbreaks in cattle have been described in many European countries. In Belgium, infections caused by Anaplasma phagocytophilum have been reported in humans and dogs; however this paper details the first report of ehrlichiosis in cattle herds in Belgium. The first case described was in a dairy herd located in east Belgium. Clinical signs included hyperthermia, polypnea and swelling of the limbs. The other case was diagnosed in a second, mixed purpose, herd in west Belgium. Within the second herd all of the affected animals came from the same pasture. All animals in that pasture showed recurrent hyperthermia and some also showed signs of mastitis and late-term abortions. Blood smears and serology revealed the presence of Anaplasma phagocytophilum in the majority of animals with pyrexia. Furthermore, the presence of leptospirosis, Neospora caninum and Q fever antibodies was tested by serological analysis but all results were negative. Paired serology for Adenovirus, BHV-4, BHV-1, BVD, PI3 and RSV-B did not show any significant seroconversion. Milk samples from cows affected by mastitis revealed minor pathogens. Fecal testing for the presence of Dictyocaulus viviparus in the first herd was negative. Recurrent pyrexia in pastured cattle is a non-specific sign, and can be related to several different pathogens. Bovine ehrlichiosis is transmitted by the tick species Ixodes ricinus which is known to be present throughout Belgium. Belgian practitioners should include ehrlichiosis in their differential diagnosis when confronted with pastured cattle suffering from recurrent pyrexia. [less ▲]

Cardiovascular consequences of septic shock are well described in humans but these hemodynamic disturbances have not yet been studied in endotoxic horses. The endotoxins act directly and indirectly to ... [more ▼]

Cardiovascular consequences of septic shock are well described in humans but these hemodynamic disturbances have not yet been studied in endotoxic horses. The endotoxins act directly and indirectly to cause a myocardial depression associated with a systemic hypotension responsible for a fall of both the cardiac output and the systemic vascular resistance in end-stage endotoxic shock. The hypothesis was that myocardial depression was a component of endotoxic shock in horses. In this way, fifty horses admitted in clinic with signs of endotoxic shock and 17 healthy control horses were submitted to a doppler echocardiographic exam to assess the impact of endotoxic shock on equine cardiac function. A shock score from 1 to 4, based on clinical evaluation, non invasive systolic blood pressure, and blood tests was attributed to each endotoxic horse. Echocardiographic and Doppler parameters were compared between the 5 groups using a multivariable ANOVA analysis. Score 1, 2, 3 and 4 groups included 11, 17, 12 and 10 horses, respectively. Some markers of systolic function included the ejection time (ET), ET corrected for HR and mean velocity of circumferential fibre shortening corrected for HR, the aortic velocity time integral and deceleration time, and the stroke volume were significantly lower, whereas the HR and the peak velocity of the late diastolic filling of the mitral Doppler flow and its velocity time integral were significantly higher in endotoxemic horses than in controls. Thanks to an increase in HR, the cardiac output was not significantly different between groups. Even if the tachycardia, the fall in preload and a probable decrease in afterload doubtless influence the observed changes, the results of this study suggest that a myocardial depression with both an impaired systolic and diastolic left ventricular function could be a component of endotoxic shock in horses. [less ▲]

Endotoxemia is the first mortality cause in intensive care horses. In human, hemodynamic disturbances have been showed to be associated with septic shock whereas in horses, this facet of endotoxemia has ... [more ▼]

Endotoxemia is the first mortality cause in intensive care horses. In human, hemodynamic disturbances have been showed to be associated with septic shock whereas in horses, this facet of endotoxemia has not yet been studied. The aim of the study was to assess the impact of endotoxin shock on equine cardiac function. Fifty horses admitted in clinic with signs of endotoxic shock and 17 healthy control horses were submitted to a doppler echocardiographic exam. The endotoxemic horses were classified in 4 groups according to their shock score based on clinical evaluation (heart rate (HR) and respiratory rate), non invasive systolic blood pressure, and blood tests (Packed cell volume and lactates). Score 1, 2, 3 and 4 groups included 11, 17, 12 and 10 horses, respectively. Left ventricular (LV) echocardiographic and Doppler parameters were compared between the 5 groups using a multivariable ANOVA analysis. The LV internal diameter, ejection time, ejection time corrected for HR and mean velocity of circumferential fiber shortening corrected for HR, the aortic velocity time integral and deceleration time, and the stroke volume were significantly lower, whereas the HR and the peak velocity of the late diastolic filling of the mitral Doppler flow and its velocity time integral were significantly higher in grade 2 to 4 endotoxemic horses than in control horses. Because of the tachycardia compensating the lower stroke volume in endotoxemic horses, the cardiac output was not significantly different between groups. Despite the fact that the increase in HR, the fall in preload and a probable decrease in afterload doubtless played a role in the observed changes, the results of this study suggest an impaired systolic and diastolic LV function in horses with moderate to severe endotoxemia. Doppler echocardiographic monitoring of the cardiovascular function could thus be of interest in equine intensive care. [less ▲]

Osteochondrosis (OC) is a developmental disease that affects growing horses and that severely affects their ability to perform. The genetic basis of its pathogenesis is poorly understood. The aim of the ... [more ▼]

Osteochondrosis (OC) is a developmental disease that affects growing horses and that severely affects their ability to perform. The genetic basis of its pathogenesis is poorly understood. The aim of the study was to analyze the transcript profile of leukocytes from horses affected with OC. Two transcriptome libraries were constructed from leukocytes of OC-affected and non-OC-affected horses using digital gene expression analysis (DGE) and real-time PCR. Statistical analysis allowed selection of 1,008 tags upregulated in the non-OC-affected group and 1,545 tags upregulated in the OC-affected group. Among these genes, 16 regulated genes and 5 housekeeping genes were selected. Metabolic pathways analysis showed an obvious dysregulation of several signaling pathways related to cartilage formation or cartilage repair, including Wnt, Indian hedgehog, and TGF-beta signaling. Other genes, including ISG, ApoB, MGAT4, and TBC1D9, showed a significantly different expression between groups. These genes may play a role in high carbohydrate diet, abnormal insulin metabolism, or inflammation, mechanisms suspected to be involved in OC. This DGE analysis of the transcript profile of leukocytes from OC-affected horses demonstrated significant differences in comparison to the control library. These results open new perspectives for the understanding of equine OC. (c) 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res. [less ▲]

OBJECTIVE: To assess the influence of age on pulmonary hemodynamics and hemorheological properties in healthy dogs. ANIMALS: 14 healthy Beagles. PROCEDURES: Dogs were placed in 2 age groups as follows ... [more ▼]

OBJECTIVE: To assess the influence of age on pulmonary hemodynamics and hemorheological properties in healthy dogs. ANIMALS: 14 healthy Beagles. PROCEDURES: Dogs were placed in 2 age groups as follows: young dogs (<or= 5 years old; n = 8) and old dogs (>or= 8 years old; 6). Hematologic characteristics, plasma total protein and fibrinogen concentrations, and blood viscosity were measured. Systolic time intervals of pulmonary blood flow were recorded by pulsed-wave Doppler echocardiography. Early (E') and late (A') diastolic myocardial velocities, isovolumic contraction velocity, and systolic myocardial velocity of the free tricuspid annulus were recorded by pulsed-wave tissue Doppler imaging (TDI). Dogs were anesthetized and pulmonary arterial pressures (PAP) and cardiac output were recorded with a pediatric thermodilution Swan-Ganz catheter. RESULTS: Hemorheological measurements were not different between the 2 groups. Systolic, mean, and diastolic PAP were higher in old dogs, compared with values in young dogs; this difference was attributed to a high pulmonary vascular resistance and low arterial compliance in old dogs. Systolic time intervals of pulmonary blood flow stayed unchanged. The A' wave of the free tricuspid annulus was increased in old, compared with that young dogs, and the E':A' ratio was decreased. Pulmonary vascular resistance was inversely correlated with compliance. CONCLUSIONS AND CLINICAL RELEVANCE: The age of dogs should be taken into account when interpreting pulmonary hemodynamic results and TDI variables of right ventricular diastolic function. [less ▲]

Equine neutrophil elastase (NE) is a protease released in inflammatory diseases and participating in tissue destruction. To measure NE in horse plasma to assess its role in pathological conditions, we ... [more ▼]

Equine neutrophil elastase (NE) is a protease released in inflammatory diseases and participating in tissue destruction. To measure NE in horse plasma to assess its role in pathological conditions, we purified elastase from equine neutrophils by a double step chromatography and obtained a pure protein of 27kDa, 4kDa smaller than the NE 2A previously purified (Scudamore et al., 1993; Dagleish et al., 1999), which was likely to be NE 2B. We developed an ELISA by using two specific polyclonal antibodies obtained from rabbit and guinea pig. The sandwich complex was detected using a secondary antibody conjugated to alkaline phosphatase. The ELISA showed good precision and accuracy, with intra- and inter-assay coefficients of variation below 10% for equine NE concentrations ranging from 1.875 to 60ng/ml. A stable plasma NE value, unaffected by the delay of centrifugation (over 4h), was obtained with plasma from EDTA anticoagulated blood. The mean value (+/-SEM) measured in 37 healthy horses was 32.53+/-4.6ng/ml. NE level in plasma of horses with colic at the time of admission was significantly higher than in healthy horses. Our results indicate that the ELISA technique we developed to measure plasmatic NE is a powerful tool for studying the role of elastase in equine inflammatory disease. In future, the application will be extended to other equine biological fluids. [less ▲]

The objective of this study was to compare the repeatability of echocardiographic measurements obtained from different echocardiographic modes and views in healthy adult equids of various sizes, breeds ... [more ▼]

The objective of this study was to compare the repeatability of echocardiographic measurements obtained from different echocardiographic modes and views in healthy adult equids of various sizes, breeds and thorax shapes. Ten, free of cardiac disease, equids (body weight: 120 to 662 kg; age: 1 to 26 years) from various breeds were used in this study. Each animal was submitted to a standardized echocardiographic and Doppler protocol 3 times at 1 day interval. This protocol included the measurements of left and right ventricular, aortic, pulmonary, and left atrial parameters obtained from different views using the bidimensional (2D) or the motion (M) modes, and the measurement of several parameters of blood flow obtained from the pulsed wave Doppler mode. Repeatability of each measurement was estimated on the basis of the residual variance using a linear model and the coefficient of variation of repeated measurements. A two by two comparison of the repeatability of measurements performed in different views was performed using the residual variances in a variance ratio F test. Results showed that repeatability of echocardiographic or Doppler measurements in equids of various sizes, breeds and thorax shapes are comparable to previously reported results in thoroughbred and standardbred horses. Left ventricular morphologic parameters showed a good repeatability in the classic M-mode right parasternal short axis (Sax) view at the level of the chordae tendinae, but the 2D-mode right parasternal long axis (LAx) four- chambers view appeared to offer an interesting alternative to measure them. This latter view also allowed obtaining the mostre repeatable measurement of right ventricular internal diameter. The left atrial diameter was maximal and most repeatable in the 2D-mode left parasternal long axisLAx four- chambers angled view, and the repeatability of the aortic diameter was best in the 2D-mode right parasternal long axisLAx five-chambers view. Finally, aortic systolic time intervals were more repeatable when measured from the Doppler mode as compared to the M-mode. ThusIn conclusion, best repeatability of echocardiographic measurements in horses could be optimized following an echocardiographicthe following protocol in equids: 1-M-mode right parasternal short axis view at the level of chordae tendinae, to measure left ventricular morphologic parameters, and 2D-mode right parasternal long axis four-chamber as an alternative view. 2-2D-mode right parasternal long axis five-chambersre, to measure the aortic diameter. 3-2D-mode left parasternal long axis four-chambersre angled view, to measure the left atrial diameter. [less ▲]

The objective of this study was to confirm the practical value of high-resolution respirometry (HRR) applied to biopsies to determine, in horses, the level of training, their athletic ability and for the ... [more ▼]

The objective of this study was to confirm the practical value of high-resolution respirometry (HRR) applied to biopsies to determine, in horses, the level of training, their athletic ability and for the early detection of muscular dysfunction. Materials and methods – The muscle mitochondrial respiration was determined by HRR in 20 endurance horses and 10 trotters sampled at the triceps brachii at different stages of their training. Results – Training increases mitochondrial respiration, in addition, the best performers had the highest rate of respiration. A trotter had abnormally low levels of muscle mitochondrial respiration for its level of training. This horse has presented several episodes of rhabdomyolysis during its racing season. Discussion – The biopsy is easily achievable by the attending veterinarian. This study shows that the athletic ability of horses is closely linked to respiratory muscle function, and suggests the value of HRR for performance prediction. In addition, the RHR has the ability to demonstrate mitochondrial dysfunction potentially responsible for exercise-induced rhabdomyolysis. [less ▲]